Fix lossy_comp_test sdlcomp_test_(float|double) for Vorbis (#426)
Fix lossy_comp_test sdlcomp_test_(float|double) for Vorbis (#426)

While experimenting, determined that Vobis' analysis stops working on
non-normalized floating point input outside the range of [2000.0, -2000.0], and
seems to get worse the larger the magnitude. As the sdlcomp_test_float and
sldcomp_test_double tests work with non-normalized floats with a magnitude of
32000.0, this explains why they do not work for Vorbis.

This patch fixes the test by reducing the magnitude of the test data at encode
and restoring it at decode if it detects Vorbis, mantaining the same 32000.0
overall magnitude so the envelope values for the test are the same as they are
for other tests and format.

It is unknown at this time if the input range magnitude of 2000.0 is  a
limitation of Vorbis or libvorbis.
libsndfile/libsndfile,erikd/libsndfile,evpobr/libsndfile,libsndfile/libsndfile,erikd/libsndfile,evpobr/libsndfile,libsndfile/libsndfile,evpobr/libsndfile,erikd/libsndfile,evpobr/libsndfile,erikd/libsndfile,evpobr/libsndfile,libsndfile/libsndfile,libsndfile/libsndfile,erikd/libsndfile